The present invention relates to a method and apparatus for controllably varying the flow rate and pressure of refrigerant fluid delivered to an evaporator in a refrigerant system of the type wherein two condensers operating at different temperatures and pressures are alternatively actuated. The invention has particular utility in systems of the type disclosed in my aforementioned prior patent applications wherein purified ice pieces are formed from tap water and then selectively melted to provide purified water.
In my aforesaid patent applications I disclose systems wherein heat to melt ice pieces is derived from a condenser employed in the ice-maker refrigeration cycle. Provision is made to maintain the condensing temperatures (and, therefore, the condensing pressures) at appropriately high levels while the condenser rejection heat is employed to melt the ice pieces. These high temperatures and pressures serve to maintain an adequate flow of refrigerant fluid through the metering device to the evaporator of the refrigeration system.